ABSTRACT

Local coastal instability, in the vertical sense, can be shown by producing evidence of any one of the following: (1) warped or offset water plane (e.g., on a wave-cut cliff); (2) distorted coastal stream gradient; (3) local evidence of compaction; (4) starved delta or incomplete floodplain (Magdalena River style); (5) vertical offset of Holocene coastal features (faulting); or (6) distortion of a beach ridge system.

On the other hand, stability (for the pertinent time span) can be shown where a wide beach ridge plain produces the same detailed sea-level history as has been determined from the model beach ridge plain in extreme northern Denmark; where the average heights of beach ridge sets in a wide system do not vary from oldest to youngest (with certain well-defined exceptions); and where the water-plane for any one ridge-swale pair does not change height from one end of the ridge to the other. It is the purpose of the present paper to examine this relationship.